How do i read the following file which has columns of data with header and space or tab delimited, in Haskell 98.
How can i access each element in the input file for example if this 4 by 7 matrix, accessing [1][2] gives YR.
Also how to get the difference in dates in Haskell 98
ID YR MO DA YrM MoM DaM
100 2010 2 20 2010 8 30
110 2010 4 30 2010 9 12
112 2010 8 20 2010 10 20
For the former, readFile, lines, and unfoldr are your friends. For the latter, see Data.Time, which is also well documented.
unfoldr by words and then everything is extremely straightforward. To be really exhaustive, map will be useful as well.readFile gives you back a string. lines splits a string into lines (i.e. a list of strings). words splits on whitespace rather than just newlines, so it can give you a list of words in a line. Those and many more are documented here: haskell.org/ghc/docs/6.12.2/html/libraries/base-4.2.0.1/…This is a short demo using readFile, (!!), map, words, and lines:
> f <- readFile "test.txt"
> ((map words $ lines f) !! 0) !! 1
"YR"
It's probably not exactly what you want, but should get you on the right track. Keep in mind that this is implementing your solution using lists rather than an array.
Forgot to mention, stick your matrix data into a file named test.txt.
